In the field of fine chemicals or drug synthesis, the temperature control requirements during the reaction process are extremely strict. For example, in the drug synthesis, a temperature difference of several degrees would cause a change of the chemical composition of the product. The traditional temperature control system adopts the convection-heating method, and the reaction speed is relatively slow. The chemical reaction is often completed but the temperature is still at the relaxation time. In order to accurately control the reaction temperature, a micro reactor suitable for the synthesis of heat-sensitive substances has been developed. The micro reactor is a three-dimensional structural element, which is made of solid substrates using special micromachining techniques and can be used to perform chemical reactions. The micro reactor typically contains a smaller channel size (0.01 to 1 mm) and channel diversity. Fluids can flow and react as required in these channels. Microfabricated chemical devices have a very large ratio of surface area to volume, and thus it enables the accurate control of the fluid temperature in a micro channel multiphase reaction system. At present, the micro channel reactor has been widely used, especially in the field of drug development or fine chemicals.
The flow state of the fluid in the micro channel is generally laminar, which will result in a poor heat transfer capability of the fluid itself. Especially when the channel size is enlarged to the millimeter level, the actual need of reaction is far from being met only by diffusion heat and mass transfer. In order to solve the above problems, the micro channel is usually machined into various shapes. The purpose is to use the secondary flow generated by these structures to enhance the heat and mass transfer, but there are disadvantages of complicated machining technology and high machining costs. In addition, the existing micro channel reactor also have the following two disadvantages: 1. The heat and mass transfer capacity of the micro channels can only be adjusted by the flow rate; the adjustment range is relatively narrow; the portability of the device is poor and the reactor has to be designed according to different reaction; 2. Chemical reactions in which solid product is formed can easily lead to micro channel blocking. Therefore, the development of a new type of micro reactor with a simple structure, and a wide range of adjustment of heat and mass transfer capacity, and a certain anti-blocking function has become an urgent need in the field of micro chemical reactions. In the meantime, the new type of micro reactor is required to be able to achieve rapid mixing, heat exchange and reaction within a narrow range, and to be able to achieve a wide range of regulation and control of experimental conditions.
Chinese invention patent CN104959093A discloses a method for solving the problem of blocking due to particles in channels of a micro reactor. At regular intervals, the cylinder with the micro channels engraved on the surface is disassembled for cleaning. The micro reactor needs to be disassembled and washed regularly, which is inconvenient to use. Chinese invention patent CN104923137A discloses a method for enhancing the mixing of multiple fluids in a micro reactor. This method requires the use of ultrasonic equipment to cause fluid oscillations, and the apparatus is relatively complicated. Chinese invention patent CN102618063A discloses a method for preparing a water-soluble azo dye continuously by the chaos mixing of a spiral tube. The method uses a spiral tube to generate secondary flow to enhance heat and mass transfer, but its heat and mass transfer effect cannot be adjusted. Chinese invention patent CN103328092A discloses an oscillating flow micro reactor, which mainly achieves the effect of enhancing mixing by the design of staggered flow, but the reactor structure is complicated to be machined. The above patents mainly consider how to achieve the prevention of the solid blocking of micro channels and how to achieve the technology of reinforcement and mixing. The dynamic regulation and control requirements of the mixing heat and mass transfer of the reactor are not taken into account. At the same time, the design of the product has defects of the complicated machining and too high manufacturing cost. With the development of micro channel reactors in the direction of generalization, portability, and multiphase, the requirements for the automatic adjustment of heat exchange and mixing of the micro reactor and for the anti-blocking performance of the reactor are becoming higher and higher. This requires a new type of micro chemical reactor to be designed to meet these needs.